package com.wzy.wc;
import org.apache.flink.api.common.typeinfo.Types;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.operators.AggregateOperator;
import org.apache.flink.api.java.operators.DataSource;
import org.apache.flink.api.java.operators.FlatMapOperator;
import org.apache.flink.api.java.operators.UnsortedGrouping;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.util.Collector;

public class BatchWordCount {
    public static void main(String[] args) throws Exception {
        // 1.创建执行环境
        ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

        // 2.从文件中读取数据
        DataSource<String> stringDataSource = env.readTextFile("input/word.txt");

        // 3.将每行数据扁平化
        FlatMapOperator<String, Tuple2<String, Long>> wordAddOneTuple = stringDataSource.flatMap((String line, Collector<Tuple2<String, Long>> out) -> {
            String[] words = line.split(" ");
            for (String word : words) {
                out.collect(Tuple2.of(word, 1L));
            }
        }).returns(Types.TUPLE(Types.STRING, Types.LONG));

        // 4.按照word分组
        UnsortedGrouping<Tuple2<String, Long>> wordAndGroup = wordAddOneTuple.groupBy(0);

        // 5.分组进行聚合
        AggregateOperator<Tuple2<String, Long>> sum = wordAndGroup.sum(1);

        // 6.打印结果
        sum.print();
    }
}
